The resistance evaluation of the Yr genes to the main prevalent pathotypes of Puccinia striiformis f. sp. tritici in China Screening of monogenic differentials of rice for differentiating the pathotypes of indica rice blast isolates in South China RACE POPULATION TREND OF PUCCINI A GRAMINIS F. SP. TRITICI IN 1990-1994 IN CHINA Population genetic structure and its variation of rice blast fungus in long-grained nonglutinous rice growing regions in Sichuan RACE DYNAMIC OF PUCCINIA GRAMINIS F. SP. TRITICI IN CHINA IN 1993